Evidence quality
Reporting bias
Distortion caused when some measured outcomes or analyses are selectively reported.
What it means
Definition
Reporting bias. Reporting bias arises when studies emphasise favourable outcomes and omit or downplay less favourable ones. It is especially important when trial protocols list many outcomes.
What it can tell you
It can help clarify what sort of evidence or claim is being discussed.
What it cannot tell you
It cannot, by itself, prove that the headline is accurate or clinically important.
Headline trap
Why this matters in headlines
A paper may highlight a positive secondary outcome while the main outcome was negative.